1. Field of the Invention
The present invention relates to a scanning line converting apparatus suitable for use in a case, for example, when a video-signal from a computer is displayed by an optional monitor or recorded in a video cassette recorder (VCR) and the like, or a reproduced video signal is displayed by an optional monitor.
2. Description of the Related Art
For example, when the video signal from the computer is displayed by an optional monitor or recorded in the VCR and the like, the number of the scanning lines of the video signal from the computer or the like must be converted into another one in accordance with a signal format set in the monitor or the VCR. Therefore, a large number of scanning line converting apparatus have been put into practice.
However, when such scanning line converting apparatus is used to convert the number of scanning lines or the like, if the signal formats of, for example, the computer and the monitor are different from each other, aspect ratios (a ratio of a frame width to a frame length) of active pictures displayed on picture screens thereof may be different from each other. If the picture based on one signal format is displayed by a display device employing another signal format as it is, then the picture is distorted. In other words, since, when the scanning line converting apparatus is used, an optional monitor may be employed. Therefore, the distortion of the picture resulting from the difference of the aspect ratio becomes a bar to properly adjust a display device such as a monitor or the like. Some of the scanning line converting apparatus have a function to freely adjust an aspect ratio of an output signal therefrom. In this case, it is disadvantageously impossible to determine whether or not a picture indicated by the output signal has a proper aspect ratio.
In view such aspect, it is an object of the present invention to provide a scanning line converting apparatus which, even if an aspect ratio set for the monitor is different from that of an input signal, can prevent a picture from being distorted.
According to an aspect of the present invention, a scanning line converting apparatus according to the present invention is one for converting the number of scanning lines of an input video signal into an arbitrary number of the scanning lines thereof to form an output image signal, and includes a discriminating means for discriminating an aspect ratio of a picture formed in accordance with a format of the input video signal and a display means for displaying the discriminated aspect ratio.
Since the discriminating means discriminates the aspect ratio of the picture indicated by the input image signal and the display means displays the discriminated aspect ratio by a numerical value, it is possible to adjust the monitor to display a picture of a proper aspect ratio based on the numerical value of the displayed aspect ratio.